There are, as you said, MANY threads on London hotels, even from the last year.
If you want specific advice, you could do people the favour of being clear about what you want:
Who are travelling with?
Kids? Ages if so?
Size of budget?
Reason for trip / any need to be in a certain location?
Requirements - classic / modern, pool, food, view, room size important?
It is a pointless exercise to discuss whether the Ritz is better than the Metropolitan without any idea of what you want.